Calibrated measurements of photonic power converters under monochromatic laser illumination

Photonic power converters (PPCs) (a.k.a. PV laser power converters) are key components in power-by-light applications such as optical wireless power transfer (OWPT) and power over fiber (PoF). Advancing research, development and commercial deployment in these areas requires precise knowledge of PPCs’ performance characteristics, including accurate current-voltage behavior and calibrated power conversion efficiency. This work presents a measurement procedure developed at Fraunhofer ISE for accurate PPC characterization under laser light - a method particularly relevant for multi-junction PPCs with overlapping subcell responses, given their sensitivity to the incident spectrum. Furthermore, this study emphasizes the importance of adopting calibrated methodologies to evaluate PPC performance and quantitatively investigates various sources of uncertainty. Therefore, an in-depth analysis of the equipment in use, aspects related to the device under test (front grid, architecture: multi-junction, thin-film), the influence of inhomogeneous cell illumination and other properties of the incident light (power, spatial distribution, spectral shape) was conducted.